Product Kit · 1.0.0
Pixels stay browser-local
Image Delivery Production Kit
Turn one browser-local image into bounded responsive variants, accurate srcset markup, integrity metadata, and a truthful pixel-memory delivery receipt.
Web developers preparing responsive image files locally before manually adding them to a site or asset pipeline.
Delivery receipt
[
{
"filename": "hero-launch-320w.webp",
"width": 320,
"height": 168,
"pixels": 53760,
"decoded_rgba_bytes": 215040
},
{
"filename": "hero-launch-640w.webp",
"width": 640,
"height": 336,
"pixels": 215040,
"decoded_rgba_bytes": 860160
},
{
"filename": "hero-launch-960w.webp",
"width": 960,
"height": 504,
"pixels": 483840,
"decoded_rgba_bytes": 1935360
},
{
"filename": "hero-launch-1200w.webp",
"width": 1200,
"height": 630,
"pixels": 756000,
"decoded_rgba_bytes": 3024000
},
{
"filename": "hero-launch-320w.jpg",
"width": 320,
"height": 168,
"pixels": 53760,
"decoded_rgba_bytes": 215040
},
{
"filename": "hero-launch-640w.jpg",
"width": 640,
"height": 336,
"pixels": 215040,
"decoded_rgba_bytes": 860160
},
{
"filename": "hero-launch-960w.jpg",
"width": 960,
"height": 504,
"pixels": 483840,
"decoded_rgba_bytes": 1935360
},
{
"filename": "hero-launch-1200w.jpg",
"width": 1200,
"height": 630,
"pixels": 756000,
"decoded_rgba_bytes": 3024000
},
{
"filename": "hero-launch-320w.png",
"width": 320,
"height": 168,
"pixels": 53760,
"decoded_rgba_bytes": 215040
},
{
"filename": "hero-launch-640w.png",
"width": 640,
"height": 336,
"pixels": 215040,
"decoded_rgba_bytes": 860160
},
{
"filename": "hero-launch-960w.png",
"width": 960,
"height": 504,
"pixels": 483840,
"decoded_rgba_bytes": 1935360
},
{
"filename": "hero-launch-1200w.png",
"width": 1200,
"height": 630,
"pixels": 756000,
"decoded_rgba_bytes": 3024000
}
]Plan / generated metadata envelope
{
"ok": true,
"schema_version": "utilito.product-kit.v1",
"kit": {
"id": "image-delivery-production-kit",
"version": "1.0.0"
},
"result": {
"status": "metadata_plan_only",
"generated": false,
"source": {
"animated": false,
"animation_known": true,
"bytes": 245760,
"has_alpha": true,
"height": 630,
"id": "hero-main",
"mime": "image/png",
"name": "hero-launch.png",
"width": 1200
},
"formats": [
"image/webp",
"image/jpeg",
"image/png"
],
"widths": [
320,
640,
960,
1200
],
"quality": {
"jpeg": 0.82,
"webp": 0.8
},
"alpha_policy": {
"background": "#FFFFFF",
"jpeg": "flatten"
},
"animation_policy": "flatten_first_frame",
"sizes": "(max-width: 640px) 100vw, (max-width: 960px) 960px, 1200px",
"fallback_format": "image/jpeg",
"limits": {
"max_dimension": 8192,
"max_output_bytes": 10000000,
"max_pixels": 16777216,
"max_source_bytes": 10000000,
"max_total_output_bytes": 25000000,
"max_working_set_bytes": 134217728
},
"variants": [
{
"filename": "hero-launch-320w.webp",
"mime": "image/webp",
"width": 320,
"height": 168,
"descriptor": "320w",
"pixels": 53760,
"decoded_rgba_bytes": 215040,
"quality": 0.8,
"quality_effective": true,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-640w.webp",
"mime": "image/webp",
"width": 640,
"height": 336,
"descriptor": "640w",
"pixels": 215040,
"decoded_rgba_bytes": 860160,
"quality": 0.8,
"quality_effective": true,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-960w.webp",
"mime": "image/webp",
"width": 960,
"height": 504,
"descriptor": "960w",
"pixels": 483840,
"decoded_rgba_bytes": 1935360,
"quality": 0.8,
"quality_effective": true,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-1200w.webp",
"mime": "image/webp",
"width": 1200,
"height": 630,
"descriptor": "1200w",
"pixels": 756000,
"decoded_rgba_bytes": 3024000,
"quality": 0.8,
"quality_effective": true,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-320w.jpg",
"mime": "image/jpeg",
"width": 320,
"height": 168,
"descriptor": "320w",
"pixels": 53760,
"decoded_rgba_bytes": 215040,
"quality": 0.82,
"quality_effective": true,
"alpha_behavior": "flattened_to_#FFFFFF",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-640w.jpg",
"mime": "image/jpeg",
"width": 640,
"height": 336,
"descriptor": "640w",
"pixels": 215040,
"decoded_rgba_bytes": 860160,
"quality": 0.82,
"quality_effective": true,
"alpha_behavior": "flattened_to_#FFFFFF",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-960w.jpg",
"mime": "image/jpeg",
"width": 960,
"height": 504,
"descriptor": "960w",
"pixels": 483840,
"decoded_rgba_bytes": 1935360,
"quality": 0.82,
"quality_effective": true,
"alpha_behavior": "flattened_to_#FFFFFF",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-1200w.jpg",
"mime": "image/jpeg",
"width": 1200,
"height": 630,
"descriptor": "1200w",
"pixels": 756000,
"decoded_rgba_bytes": 3024000,
"quality": 0.82,
"quality_effective": true,
"alpha_behavior": "flattened_to_#FFFFFF",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-320w.png",
"mime": "image/png",
"width": 320,
"height": 168,
"descriptor": "320w",
"pixels": 53760,
"decoded_rgba_bytes": 215040,
"quality": null,
"quality_effective": false,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-640w.png",
"mime": "image/png",
"width": 640,
"height": 336,
"descriptor": "640w",
"pixels": 215040,
"decoded_rgba_bytes": 860160,
"quality": null,
"quality_effective": false,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-960w.png",
"mime": "image/png",
"width": 960,
"height": 504,
"descriptor": "960w",
"pixels": 483840,
"decoded_rgba_bytes": 1935360,
"quality": null,
"quality_effective": false,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
},
{
"filename": "hero-launch-1200w.png",
"mime": "image/png",
"width": 1200,
"height": 630,
"descriptor": "1200w",
"pixels": 756000,
"decoded_rgba_bytes": 3024000,
"quality": null,
"quality_effective": false,
"alpha_behavior": "alpha_preserved_if_decoder_exposes_it",
"animation_preserved": false,
"first_frame_only": false,
"generated": false,
"encoded_bytes": null,
"sha256": null,
"actual_digest": false,
"recomputed": false,
"provenance": "planned_metadata_only"
}
],
"srcsets": {
"image/webp": "hero-launch-320w.webp 320w, hero-launch-640w.webp 640w, hero-launch-960w.webp 960w, hero-launch-1200w.webp 1200w",
"image/jpeg": "hero-launch-320w.jpg 320w, hero-launch-640w.jpg 640w, hero-launch-960w.jpg 960w, hero-launch-1200w.jpg 1200w",
"image/png": "hero-launch-320w.png 320w, hero-launch-640w.png 640w, hero-launch-960w.png 960w, hero-launch-1200w.png 1200w"
},
"picture_snippet": "<picture>\n <source type="image/webp" srcset="hero-launch-320w.webp 320w, hero-launch-640w.webp 640w, hero-launch-960w.webp 960w, hero-launch-1200w.webp 1200w" sizes="(max-width: 640px) 100vw, (max-width: 960px) 960px, 1200px">\n <source type="image/png" srcset="hero-launch-320w.png 320w, hero-launch-640w.png 640w, hero-launch-960w.png 960w, hero-launch-1200w.png 1200w" sizes="(max-width: 640px) 100vw, (max-width: 960px) 960px, 1200px">\n <img src="hero-launch-1200w.jpg" srcset="hero-launch-320w.jpg 320w, hero-launch-640w.jpg 640w, hero-launch-960w.jpg 960w, hero-launch-1200w.jpg 1200w" sizes="(max-width: 640px) 100vw, (max-width: 960px) 960px, 1200px" width="1200" height="630" alt="">\n</picture>",
"memory_table": [
{
"filename": "hero-launch-320w.webp",
"width": 320,
"height": 168,
"pixels": 53760,
"decoded_rgba_bytes": 215040
},
{
"filename": "hero-launch-640w.webp",
"width": 640,
"height": 336,
"pixels": 215040,
"decoded_rgba_bytes": 860160
},
{
"filename": "hero-launch-960w.webp",
"width": 960,
"height": 504,
"pixels": 483840,
"decoded_rgba_bytes": 1935360
},
{
"filename": "hero-launch-1200w.webp",
"width": 1200,
"height": 630,
"pixels": 756000,
"decoded_rgba_bytes": 3024000
},
{
"filename": "hero-launch-320w.jpg",
"width": 320,
"height": 168,
"pixels": 53760,
"decoded_rgba_bytes": 215040
},
{
"filename": "hero-launch-640w.jpg",
"width": 640,
"height": 336,
"pixels": 215040,
"decoded_rgba_bytes": 860160
},
{
"filename": "hero-launch-960w.jpg",
"width": 960,
"height": 504,
"pixels": 483840,
"decoded_rgba_bytes": 1935360
},
{
"filename": "hero-launch-1200w.jpg",
"width": 1200,
"height": 630,
"pixels": 756000,
"decoded_rgba_bytes": 3024000
},
{
"filename": "hero-launch-320w.png",
"width": 320,
"height": 168,
"pixels": 53760,
"decoded_rgba_bytes": 215040
},
{
"filename": "hero-launch-640w.png",
"width": 640,
"height": 336,
"pixels": 215040,
"decoded_rgba_bytes": 860160
},
{
"filename": "hero-launch-960w.png",
"width": 960,
"height": 504,
"pixels": 483840,
"decoded_rgba_bytes": 1935360
},
{
"filename": "hero-launch-1200w.png",
"width": 1200,
"height": 630,
"pixels": 756000,
"decoded_rgba_bytes": 3024000
}
],
"working_set": {
"source_decoded_rgba_bytes": 3024000,
"projected_variant_decoded_rgba_bytes": 18103680,
"projected_total_decoded_working_set_bytes": 21127680,
"limit_bytes": 134217728,
"method": "source_rgba_plus_all_planned_variant_rgba_conservative"
},
"disclosures": [
{
"code": "METADATA_PLAN_ONLY",
"message": "API, MCP, and direct core output contains a deterministic metadata plan only; no image bytes were decoded or generated."
},
{
"code": "PNG_QUALITY_NOT_EFFECTIVE",
"message": "PNG canvas encoding receives no effective quality claim."
},
{
"code": "NO_UPSCALE",
"message": "Every planned width is at or below the submitted source width."
},
{
"code": "NO_HOSTING_OR_RETENTION",
"message": "Filenames are local download names only; no upload, hosting, signing, deployment, or retention occurs."
},
{
"code": "JPEG_ALPHA_FLATTEN_PLANNED",
"message": "JPEG variants require a canvas background fill of #FFFFFF before drawing."
}
],
"integrity_manifest": null,
"delivery_manifest": null,
"delivery_report": null,
"claims": {
"browser_local_pixels_required": true,
"generated_bytes": false,
"digests_computed": false,
"provenance_verified": false,
"hosted": false,
"retained": false,
"pipeline_executed": false
}
},
"receipt": {
"input_bytes": 660,
"output_bytes": 10155,
"operations": 1,
"omitted_items": 0,
"warnings": [],
"planned_variants": 12,
"realized_variants": 0,
"total_pixels": 4525920,
"total_decoded_rgba_bytes": 18103680,
"total_encoded_bytes": 0
},
"provenance": {
"deterministic": true,
"model_used": false,
"network_used": false,
"storage_used": false,
"core_versions": {
"image_delivery_production_kit": "1.0.0",
"image_delivery_audit": "utilito.image-delivery.v1",
"browser_canvas_generation": "browser-local-v1",
"integrity_manifest": "utilito.file-integrity.v1"
}
},
"error": null
}Free runnable capability
Generate and download one bounded responsive image set locally with actual integrity and delivery receipts, no signup, and no upload.
Builder capability
The existing Builder Pilot can coordinate higher bounded workflow volume; it does not add uploads, hosting, retention, deployment, signing, hidden formats, or pipeline execution.
See the existing Builder PilotPrivacy boundary
Image pixels remain browser-local. API and MCP accept strict source metadata only and return a plan; they never accept URLs, paths, base64, blobs, byte arrays, image content, hosting, storage, or retention.
Limits and truthful boundaries
- Hosted API, MCP, and direct core output is metadata-plan-only. No generated bytes, hashes, reopen checks, or provenance claims appear until the actual local File is decoded and converted by the browser adapter.
- Outputs use browser-reliable PNG, JPEG, and WebP canvas encoders only. PNG quality is not claimed effective; JPEG alpha requires explicit background flattening; canvas outputs are static and animation is rejected or explicitly reduced to the decoded first frame.
- Source files are capped at 10 MB, 8,192 px per dimension, and 16,777,216 pixels. Widths never upscale; variants are capped at 24, each output at 10 MB, all output at 25 MB, and conservative decoded working-set projection at 128 MiB before canvas allocation.
- Downloads are explicit user-click Blob URLs. They are created transactionally and revoked on input change, replacement, failure, stale generation, and pagehide. Utilito does not upload, host, sign, deploy, publish, retain, or auto-download files.
- SVG and arbitrary URL/path/content inputs are forbidden. Browser decoders vary, especially for GIF and WebP; the selected local file must pass MIME/signature checks and decode successfully. JavaScript cannot reliably identify every transparent Proxy in browsers, so browser calls are built from controlled form values.